The present invention is generally directed to fins often used in activities such as lap swimming, scuba diving, snorkeling, and surfing (“swim fins”). More particularly, the present invention is directed to the physical interface that connects a user to a swim fin blade.
Some fins attach to a user's foot utilizing pockets that are configured to receive a portion or all of a user's foot, much like a shoe. Such pockets may be constructed of either rigid or soft and flexible materials. Often, such pockets are configured to receive only a portion of a user's foot, and have an open heel or back area. In such situations, a user's foot is often held in place—inserted into the pocket—through the use of one or more straps.
However, each of these means has certain drawbacks and disadvantages. For example, in certain situations rigid foot pockets chafe the user's feet, resulting in discomfort and potential injury. This drawback is significant since swim fins are often used in scuba diving, snorkeling, and surfing—environments where abrasive materials, such as sand, is prevalent. This drawback is also significant in repetitive activities, such as lap swimming.
Pockets in swim fins made from soft and flexible materials also suffer from drawbacks and disadvantages. Soft pockets are generally more comfortable for the user, but such swim fins typically allow for unwanted motion of the user's foot relative to the swim fin blade. Unwanted motion may limit the force the user may effectively apply to the swim fin blade and may limit the size, shape, and stiffness of the swim fin blade, thus resulting in limited performance.
Additionally, regardless of whether the foot pocket is formed from a soft or rigid material, existing swim fins generally lack a secure attachment sufficient to prevent the swim fin from being forcibly removed from the user's foot when external forces are applied. Yet, in use swim fins are often exposed to external forces caused from waves, surf, currents, kelp, etc.
The prevalence of swim fins being forcibly removed is evident from the original manufacture and after-market accessory of a tether. In general, swim fin tethers comprise a mechanical attachment (for example, a strap or other connection) between the swim fin and the user. For example, a strap may connect to a swim fin and then be secured to a user's ankle. The addition or purchase of a tether increases the cost of such swim equipment and may provide other drawbacks, such as discomfort and excessive drag when used.
Further, although swim fin attachments are generally available in varying sizes, they generally lack the ability to conform to variations in foot size and shape, resulting in a poor fit.
Moreover, swim fin attachments as generally available typically present gaps and spaces between the user and the swim fin. Such gaps may cause increased hydrodynamic drag to the swimmer due to fluid flowing along the interface between the user and the swim fin. This increased drag may result in reduced performance.
Accordingly, it is desirable to provide an interface between a user and a swim fin that is comfortable—even in environments where abrasive materials are present, provides an improved fit to various foot shapes and sizes, does not allow unwanted motion, cannot be forcibly removed by external forces, and does not increase hydrodynamic drag on the swimmer. Such an interface is additionally desirable because it may allow increased fin size, various fin shapes, and/or various degrees of fin stiffness or rigidity, which may therefore result in increased swim fin performance.